geospatial location
Add geographic location, parameters (latitude, longitude, name)
Get the longitude and latitude of the specified city
Get the distance between two places
Specify the latitude and longitude as the center, find the city within the given radius
Specify the city as the center to search for cities that exist within the specified radius
The bottom layer of geo is zset
Hyperloglog
No repeating elements
Test use
bitmap
Bit storage
Statistics user information, active, inactive! Login, not logged in! Check in, check in 365! Both states can use Bitmaps! Bitmaps bitmap, data structure! All operating binary bits for recording, only 0 and 1 Two states!
Test: Seven days a week, clock in is 1, otherwise it is 0
Count the number of clock-in days
